Thread-clamping device



Feb. '12 1924,

L. E'GGER THREAD CLAMPING DEVICE Original Filed Dec. 21 1.921

Patented Feb. 12, 1924.

Original application filed December 21, 1921, Serial No. 523,989. PatentNo;1,450,914,:datedApril'lo, i 1923*. Divided and thisapplicatio'n filed December l; 1322. Serial No: 604,920.

ToaZZw/wm it m-ayconcern."

Be it known that I, LOUIS EGGER, a citizen of Switzerlandnesiding at Summiswald- 'Grunen, Switzerland, have invented certain new "and useful Improvements l in Thread- Clamping Devices, of which the'followin-g is a specification. The presentinvention has reference to-improvementsin sewing machines and relates more particularly' to-an improved clamping device for periodically clamping the stitching thread againstbeing dr awn out furtherunder theoperat-ive-pull. A clamp-ofthis-chai eater is used to advantage in connection with a book-sewing machine'such as described in my application filed-December21, 1921, Serial No. 523,989 and which has matured in Patent 'NO;' '1 ,45O,91&,--April- 10,. .1923 in .which this invention was first-disclosedwandflof which thisapplication formslawdivision, but

it may, obviously, also be used-in other; connections.- 1 1 I 1 My invention will best be understood when described '1 in cfonnection with the accompanying drawing, in which Fig. 1 is a front View of the device; Fig. 2 is a fragmentary top View, and Fig. 3 a sectionon line 33 of Fig. 1; Fig. 4-ShOWS the clamping device in section with its drive, in position on suitable supportin means.

The cross-bar 1 is rigidly mounted between the lateral machine frame standards 2 and 3 and is provided with a lurality of housings 4 presenting downwardly tapering bores 44, the number of which depends upon the number of stitching units used in the particular machine. With these bores cooperate truncated cone shaped plugs 5 in such manner that in their lowermost operative position they fit the bore tightly all round. The bore walls are slit open at one side, as at 6, to present thread introducing passages 7. For more conveniently introducing the threads, always two such passages 7 may be arranged facingly, as shown in Fig. 2, but it must be understood that this particular arrangement is not necessary and the slits may be in any other relative position, as long as they will permit the ready introduction of the thread which, prior to entering the passage, passes through the tensioning device 8 of well known construction. The thread, after having been introduced into the bore through the slit 7, is guided around the lifted plug time to someextentjtoprevent it-from slipping out again;

Fromthe top of eac hplugentends a guide m 1 i 111391103, tedtowtreel Y reciprocatezwithm a 1 1.

bridge member 10-extending from the crossa bar l and an'interposed compression spring -11 serves to normally retain the p.ug pressech home inits seat,- as clearly shown in the sev-- 1 eral fi-gures.-- The referred-to tensioners -8- e nted l on the bridge are preferably all I mou member:10.- a 1 For period-ically simultaneously and u-niformly operating the plugs there is provided a swing bar 12 fulcrumedat 13: and 14- respectivelyat 1 its extremities I on 1 bearing 1 cheeks 15 and 16 extending from the. cross. bar 1, which-swing barus anoperativeeon:

tact with the lower facesof allzof the'plugs.

'Rooking movement is imparted to this bar .111. any-su1table manner, .for. .instanceuas shown, .by.means of abellcrankifi, whose.

outer. arm 21coactswith the lowerend oftthe swlng. bar, and .whose; inner. arm 22 is acted.

on .by-a bell. crank 18.115 the intermediary. .of

the connecting link19. This bell crank 18 is pivoted at 25 on the machine frame and its inner roller end 26 is operated by a cam 20. On rotation of the latter, which preferably is fixed on the main drive shaft 23, the bell crank 17 is rockingly operated and in turn oscillates the swing bar for alternately lifting the plugs and letting them down again into their seats for respectively freeing the threads and then again temporarily securely clamping them against operative pull.

In order to vary, within limits, the lift of the plugs, the arm 21 of the bell crank 17 is provided at its free end with an adjusting screw r Obviously, the described means for operating the swing bar may be provided at both ends thereof close to each side support. A

The described mechanism forms a complete unit and can readily be mounted on a machine in exchange for a less satisfactory or worn out thread clamping device, the swing bar beingcapable of being operated in any other suitable manner than in that shown by way of example.

What I claim is 1. In a thread clamping device of the character set forth, in combination with suitable supporting means, a cross-bar rigidly mounted on said supporting means, a plurality of housings on said cross-bar presenting downwardly tapering bores, plugs adapted for reciprocal cooperation with said bores, means for normally independently retaining said plugs in their operative, thread clamping position, and means for periodically uniformly lifting them off their seats, each of said housings being split down its one side for thread introducing purposes.

2. In a thread clamping device of the character set forth, in combination with suitable supporting means, a cross-bar rigidly mounted on said supporting means, a plurality of housings presenting downwardly tapering and laterally slit bores in said bar, a bridge member rigidly secured to said cross-bar, a cone shaped plug for each housmg, a guide pinextending from each plug and a com pression spring surrounding said guide pin, the latter adapted to be guided in said bridge member, a thread tensioner on said bridge member for each housing, and means for periodically uniformly lifting all of said plugs.

3. In a thread clamping device of the character set forth, in combination with suitable supporting means, a cross-bar rigid-' ly mounted on said supporting means, a'plurality of laterally slit housings presenting downwardly tapering bores on said cross bar, abridge member rigidly secured to said cross-bar, thread tensioners on said'bridge' member, plugs adapted for reciprocal co operation with said housing bores and means plugs in their relative clamping position, means for periodically uniformly lifting all of saidplugs, comprising a swing bar pivotally mounted relative to said cross-bar and in operative contact with the lower faces of said plugs, means for imparting to said swing bar an oscillatory movement, and means for varying the operative lift of said plugs.

l. In a thread clamping device of the character set forth, in combination with suitable supporting means, a cross-bar rigidly mounted on said supporting means, a plurality of laterally slit housings presenting downwardly tapering bores on said cross-bar, a bridge member rigidly secured to said cross-bar, thread tensioners on said bridge member, plugs adapted for reciprocal cooperation with'said housing bores and means for normally retaining said plugsin their relative clamping position, means for periodically lifting said plugs, comprising a swing bar in operative contact with the lower faces of said plugs, a bell crank pivoted on said'sup porting means, one arm of which coacts with said swing bar, an adjusting member on this bell crank arm, a main drive shaft,'a1

cam fixed thereto, a second bell crank pivoted on said-supporting means and operable by; said'cam, and a connecting link between said cam operated bell crank'and said swing bar operating bell crank.

In testimony whereof I affiX my signature.

LOUIS EGGER; 

